The manufacture of semiconductor and other electronic devices, hereinafter described as work pieces, generally includes steps such as sawing, scribing, breaking, sorting, inspecting, bonding, shipping, storage and additional processing. A number of tools and methods arc employed to handle the delicate work pieces throughout such manufacturing processes.
One such method involves the use of a film that contains a pressure sensitive adhesive mounted in a vacuum frame. In this method, the work pieces are individually secured to the adhesive film by the force of the adhesive. The film securing the work pieces is secured to the frame through the application of negative pressure applied through vacuum holes. This arrangement has proven efficient and effective in handling work pieces throughout a variety of fabrication processes. Once processing is completed, however, significant problems exist in removing the fragile work pieces from the adhesive film.
One method for removing work pieces from the adhesive film involves moving the film over a rotatable roller such that the work piece rides up on the roller. A pick and place apparatus utilizing a vacuum has a bar which is aligned with a longitudinal axis of the work piece. A vacuum source exerts a force normal to the film through a channel opening in the bar, pulling the work piece from the film. This method has demonstrated a successful, i.e., undamaged, removal yield well in excess of ninety-nine percent for work pieces with dimensions no larger than 12 mils by 320 mils.
Greater functionality is being integrated into semiconductor work pieces, thus causing the need for work pieces of greater dimensions. The above-described method is less effective, resulting in a lowered removal yield, for these larger work pieces. The increased width of the larger work pieces allows the work pieces to tilt relative to the pick and place apparatus, preventing the apparatus from forming a sufficient vacuum seal on the work piece when the vacuum bar is aligned with the longitudinal axis of the work piece.
Increasing the downward force of the pick and place apparatus may cause damage to the work piece, thus lowering the removal yield. Alternatively, a pick and place apparatus may be fabricated with various size vacuum bars to handle the different size semiconductor work pieces. However, fabricating different size pick and place apparatuses would add cost to the semiconductor fabrication process, and would add downtime to the process necessary to swap out or exchange pick and place apparatuses. Thus, there exists a need for an improved method of removing semiconductor work pieces having larger dimensions.